The U.S. Coast Guard is investigating reports of a potentially massive oil sheen about 20 miles north of the site of last April’s Deepwater Horizon oil rig explosion. …

[Around 1 pm] another caller reported a much larger sheen — about 100 miles long — originating in the same area and spreading west to Cocodrie on Terrebonne Bay, Barnard said.

“We haven’t been able to verify that, and it would be very unlikely for an individual to be able to observe a 100-mile long sheen,” he said, adding inspection teams were en route around 3 p.m. to the site. …